The couple married on Saturday in the Take That star's Los Angeles mansion.
He told Hello magazine how he had taken the four Queens from the deck and written the words 'will', 'you', 'marry' and 'me' on them.
Field added: "Then he dropped on to one knee. I said 'Yes'."
Williams went on to explain the reason behind the proposal.
"When we first started going out, this weird thing would happen," he said. "When I had a deck of cards, I would split the pack and always come up with a Queen of Hearts."
He continued: "Because I'm into mysticism, it filled my heart and made me stop worrying about whether I was with the right person."
Field previously admitted that the couple's dogs had been bridesmaids at the ceremony.
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